Forget everything you thought you knew, because your favourite vanilla ice cream might not contain vanilla or cream – leaving us wondering, is it just plain ice?

The mind-boggling revelation is part of an investigation by consumer association Which?, which found one in five supermarket or branded vanilla ice creams contain no vanilla, no cream and no fresh milk.

In fact, only half of the 24 ice creams examined contained all three traditional ingredients. The remaining products contained only some, or none of the ingredients.

Of the five products with no vanilla, cream or fresh milk in them, Wall’s Soft Scoop Vanilla Ice Cream was the only that wasn’t a supermarket own-label. The other ice creams containing none of the three ingredients were Asda, Morrisons, Tesco’s own-brand Soft Scoop Vanilla Ice Cream, and Ms Molly’s - a brand exclusively sold at Tesco.

Traditionally, vanilla ice cream is made from a few simple ingredients: fresh milk, cream, egg yolks, sugar and vanilla. These ingredients are frozen and aerated to make ice cream.

However, in a number of the products researchers looked at cream and milk were substituted with partially reconstituted dried skimmed milk, and in some cases, whey protein. Meanwhile, vanilla was often replaced with a general ‘flavouring’.

Additional non-dairy ingredients in some of the ice creams included palm oil, coconut oil, palm kernel oil and water.

Until 2015, a product labelled “ice cream” in the UK had to contain at least 5% dairy fat and 2.5% milk protein. However, since the introduction of the Food Information Regulations in 2015, these rules no longer apply.

The removal of these fixed criteria was to enable more flexibility in regards to reformulation and product innovation, which has allowed for vegan products, or reduced fat products, to be sold as “ice creams”. But the removal of the original regulations has also allowed cheaper ingredients to replace those used in traditional recipes, Which? said.

As such, there are currently no requirements for manufacturers to meet before a product can be called “ice cream”. Now, only products labelled as “dairy ice cream” must contain at least 5% dairy fat, some protein from a dairy source and no vegetable fats.

“Shoppers may be surprised to find out that the vanilla ice creams available to buy in supermarkets can vary wildly in terms of the ingredients they contain,” a Which? spokesperson said.

“For those looking for a more authentic ice cream or trying to avoid controversial ingredients such as palm oil, our advice is to check the ingredients list, and look for these three key ingredients - natural vanilla, dairy cream, and fresh milk.”